Mishnah Berurah — משנה ברורה

Who recited it at home - See in Magen Avraham, Pri Megadim, and all the other Achronim who all agree that even the prayer leader who reciting the blessing at home should not repeat it in shul, because nowadays everyone is fluent [in praying] and everyone recites the blessing for themselves and they prefer to not fulfill their obligation with the prayer leaders recital. Therefore, in those places where the custom is that the prayer leader says all the blessings for the congregation, like in our area where the custom is to do so on the Yamim Noraim (ie. Rosh Hashana/Yom Kippur) - where the prayer leader recites [the blessings] for the congregation, and even recites Al Netilat Yadayim, Asher Yatzar, and the blessings of the Torah - one should be careful to not recite them at home. And if he (the prayer leader) happened to recite them at home already, he should ask one of those who are listening [to his blessings], who did not already recite the blessings themselves, to have in mind to fulfill their obligation with his blessings. However, the prayer leader must be very careful to make all the words of the blessings audible; unlike what's done in some places where the prayer leader only recites out loud the beginning and end of each blessing. Since his (the prayer leader's) intention when reciting the blessings is to fulfill another's obligation, the listener must listen to every word of the blessing.